1. Field of the Invention
The present invention relates to a recording and reproducing apparatus having an internal clock.
2. Description of the Related Art
Hitherto, the internal clock of a recording and reproducing apparatus tells the time by counting the reference clocks. When the time is deviated, the user sets the time manually.
As an automatic time calibration method of an internal clock, a method to adjust according to a broadcast time tone is known.
In this case, however, the time tone is broadcast only several times a day, and the time is not calibrated while the recording and reproducing apparatus is in record reservation, recording or reproducing state. If not calibrated for a long time in such a case, the time may be deviated. If recording is reserved in time deviation state of the internal clock, the beginning or ending portion of a program may not be recorded.
Besides, since the time tone does not include time data, it is hard to calibrate if the broadcast time of time tone and the time of the internal clock of the recording and reproducing apparatus are deviated by several minutes. For example, when the time is advanced by one hour in daylight saving time, the time cannot be calibrated. It is also difficult to calibrate if a wrong time is set in the internal clock by manual setting by the user.
The invention is devised in the light of the prior art, and the recording and reproducing apparatus of the invention comprises a time extraction unit for extracting the time information included in the received broadcast signal, a clock unit for counting the time, and a time setting unit for setting the time of the clock unit manually. By the extracted time information, the time of the clock is calibrated, and while the time information is extracted within specific intervals, manual time setting by the time setting unit is prohibited.
The time calibration method of recording and reproducing apparatus of the invention comprises (a) a step for extracting the time information included in the received broadcast signal, (b) a step for calibrating the time of the clock unit by the time information extracted at step (a), (c) a step for measuring the extraction intervals of the time information extracted at step (a), and (d) a step for prohibiting manual time setting of the clock unit when the extraction intervals measured at step (c) are within specific intervals.